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Abstract:

An elongated LED lamp suitable for replacing a fluorescent lamp in a lamp
fixture comprises a chassis having a first chassis end with two
electrodes adapted to be respectively coupled to two electrodes in the
lamp fixture supplying AC power, and a second chassis end. A light source
depends from the chassis. A power regulating circuit is mounted to the
chassis and is coupled to the two electrodes for providing DC power to
the first light source. A first light collector conditions the light it
collects light from the first light source for TIR propagation within a
side-light distribution arrangement. An elongated side-light distribution
portion depends from the chassis and receives light exiting the first
light collector. Light-extraction structure extract light from the side
of the first portion, along a length of the first portion, in a different
direction from the direction of light received from the first light
collector.

Claims:

1. An elongated LED lamp suitable for replacing a fluorescent lamp in a
lamp fixture, comprising: a) a chassis having a first chassis end with
two electrodes that are adapted to be respectively coupled to two
electrodes in the lamp fixture supplying AC power, and a second chassis
end; b) a first light source depending from the chassis, comprising at
least one LED, and being located more proximate said first chassis end
than said second chassis end; c) a power regulating circuit mounted to
the chassis and coupled to said two electrodes for providing DC power to
the first light source; d) a first light-collection means having an input
that collects at least 25 percent of the light emitted by the first light
source, and having an output that directs over half of the light
collected at the input with an angular distribution different from that
of the light when received at the input; and e) an elongated side-light
distribution arrangement having a first portion depending from the
chassis and being arranged to receive at least a majority of the light
exiting the first light-collection means, which light has an appropriate
angular distribution for total internal reflection within the side-light
distribution arrangement; the first portion comprising: i) a rod with an
elongated ii) shape having a minimum cross-sectional dimension along a
length of the first portion that exceeds 50 percent of the maximum
cross-sectional dimension along said length; and iii) light-extraction
means for extracting light from the side of the first portion, along a
length of the first portion, in a different direction from the direction
of light received from the first light-collection means.

2. The lamp of claim 1, wherein the light-extraction means extends along
a length of the first portion of the side-light distribution arrangement
for a distance greater than 50 percent of the distance between the first
and second ends of the electric lamp.

3. The lamp of claim 1, wherein the first light source comprises one or
more LED light sources, all of which are provided with a single pair of
power leads and a single lens for conditioning the light output.

4. The lamp of claim 1, wherein the chassis contains an elongated cavity
extending along a length of the chassis for containing electronic
elements.

5. The lamp of claim 4, wherein said cavity includes said power
regulating circuit.

6. The lamp of claim 1, wherein: a) the chassis supports an elongated
reflector facing the side-light distribution arrangement and shaped to
partially surround said side-light distribution arrangement about a
longitudinal axis of the side-light distribution arrangement; and b) the
reflector presenting to the side-light distribution arrangement a
non-specular, diffuse reflecting surface that is configured to reflect
light, extracted from the side-light distribution arrangement by the
light-extraction means, to a desired target area to be illuminated.

7. The lamp of claim 6, wherein the dimension of said reflecting surface
presented to the first side-light distribution portion, taken crosswise
to said longitudinal axis of said first side-light distribution portion,
being at least about 1.3 times the maximum dimension of the
light-extraction portion taken in the same plane.

8. The lamp of claim 1, wherein the distance between the first and second
chassis ends is at least about 30.5 centimeters.

9. The lamp of claim 1, wherein the first light-collection means has an
input that collects at least 75 percent of the light emitted by the first
light source.

10. The lamp of claim 1, wherein the second chassis end has two
electrodes that are adapted to be respectively coupled to electrodes in
the lamp fixture supplying AC power; and further comprising: a) a second
light source comprising at least one LED light source located more
proximate said second chassis end than first second chassis end; and b) a
power regulating circuit mounted to the chassis for providing DC power to
the second light source; c) a second light-collection means and an
associated second portion of the side-light distribution arrangement
conforming to the above-mentioned features of first light-collection,
means and the first portion of the side-light distribution arrangement,
respectively.

11. The lamp of claim 10, wherein said power regulating circuit for
providing power to the second light source is the same as said power
regulating circuit for providing power to the second light source.

12. The lamp of claim 10, wherein the first and second light sources are
located within about five centimeters of the first and second chassis
ends, respectively.

13. The lamp of claim 12, wherein the lamp is free of further light
sources located between the first and second light sources.

14. The lamp of claim 10, wherein: a) light from the first light source
passes through a distal end of the first side-light distribution portion
and passes into the second side-light distribution portion, and b) light
from the second light source passes through a distal end of the second
side-light distribution portion and passes into the first side-light
distribution portion.

15. The lamp of claim 10, wherein the first and second portions of the
side-light distribution arrangement are optically isolated from each
other.

16. The lamp of claim 10, wherein the first and second portions of the
side-light distribution arrangement are optically coupled to each other.

Description:

[0002] The use of fluorescent lighting is wide spread. Typical fluorescent
lighting consists of long slender tubes, typically 4 feet (122 cm) long
with a diameter of 1 inch (2.54 cm). This type of lighting typically has
a poor color rendering index, making color differentiation by a person
difficult. This lighting is not widely used in residential lighting due
to the poor aesthetics created by the wavelength distribution of light
output from the lamp. Many efforts have been made to utilize LEDs in
lamps used to replace fluorescent tubes. Such LED-based replacement lamps
provide advantages in that LEDs can be selected that provide color
spectrum outputs that give superior color rendering and more
aesthetically pleasing light.

[0003] One approach used in making LED-based fluorescent tube replacements
is to create a large array of LEDs that fit within a cylindrical envelope
defined by the dimensions of the fluorescent tube being replaced. Such
devices may consist of 100 or more individual LEDs. However, the output
is less desirable because the brightness created by each LED evokes a
sense of glare from the fixture. Reducing the number of LEDs while
increasing the brightness of each LED to maintain a desired light output
level only exacerbates the sensation of glare, whereas reducing the size
of the LEDs and increasing the number of LEDs increases the overall cost
of the device.

[0004] A second approach for making an LED-based fluorescent tube
replacement, as disclosed in relation to FIG. 38 of Cassarly et al. U.S.
Pat. No. 7,374,313, is to use a pair of LED light sources, one at each
end of a side-light distribution member. It would be desirable to go
beyond the foregoing disclosure and provide a means for holding the
side-light distribution member and LED light sources in place.

[0005] It would thus be desirable to provide an elongated LED lamp that
can replace an elongated fluorescent lamp, while providing a pleasing
color distribution of light without high brightness "glare" spots and
providing means for holding the side-light distribution arrangement.

BRIEF SUMMARY OF THE INVENTION

[0006] In a preferred form, the invention provides an elongated LED lamp
suitable for replacing a fluorescent lamp in a lamp fixture. The LED lamp
comprises a chassis having a first chassis end with two electrodes
adapted to be respectively coupled to two electrodes in the lamp fixture
supplying AC power, and a second chassis end. A first light source
depends from the chassis, comprises at least one LED, and is located more
proximate the first chassis end than the second chassis end. A power
regulating circuit is mounted to the chassis and is coupled to the two
electrodes for providing DC power to the first light source. A first
light-collection means has an input that collects at least 25 percent of
the light emitted by the first light source, and has an output that
directs over half of the light collected at the input with an angular
distribution different from that of the light when received at the input.
An elongated side-light distribution arrangement has a first portion
depending from the chassis and is arranged to receive at least a majority
of the light exiting the first light-collection means, which light has an
appropriate angular distribution for total internal reflection within the
side-light distribution arrangement. The first portion comprises a rod
with an elongated shape having a minimum cross-sectional dimension along
a length of the first portion that exceeds 50 percent of the maximum
cross-sectional dimension along such length. Light-extraction means
extract light from the side of the first portion, along a length of the
first portion, in a different direction from the direction of light
received from the first light-collection means.

[0007] Beneficially, the foregoing elongated LED lamp can replace an
elongated fluorescent lamp, while providing a pleasing color distribution
of light without high brightness "glare" spots and providing means for
holding the side-light distribution arrangement.

[0008] Further objects and advantages will become apparent in light of the
following disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the following drawings, like reference numbers refer to like
parts:

[0010] FIG. 1 is a side plan view of an elongated LED lamp, partially in
diagrammatic form, in accordance with an aspect of the invention.

[0011] FIG. 2 is similar to FIG. 1, but has power regulating circuits for
the LED light sources that are moved to different locations.

[0012]FIG. 3 is a cross-sectional view of an LED lamp taken at arrows 3
in FIG. 2, which is enlarged to more clearly show preferred details of
construction.

[0013] FIG. 4 is a side plan view of another elongated LED lamp, partially
in diagrammatic form, in accordance with another aspect of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] FIG. 1 shows an LED lamp 10 for replacing a fluorescent lamp in a
fluorescent lamp fixture (not shown). Typical fluorescent lighting
consists of long slender tubes, typically 4 feet (122 cm) long with a
diameter of 1 inch (2.54 cm). However, FIG. 1, as well as FIGS. 2 and 4,
illustrate lamps with a larger vertical size in relation to horizontal
size than is typical, for clarity of illustration. LED lamp 10 includes a
pair of electrode pins 12 and an associated end plate 13 at one end of
the lamp, and another pair of electrode pins 14 and an associated end
plate 15 at the other end of the lamp. Pins 12 and 14 are constructed to
match electrode pins of a standard, elongated fluorescent lamp typically
used for office lighting. In this way, the LED lamp 10 can replace a
fluorescent lamp in a fixture (not shown) by simply removing the
fluorescent lamp and replacing it with the LED lamp 10.

Chassis for Gripping and Protecting Illumination Portions of Lamp

[0015] LED lamp 10 includes a side-light distribution arrangement 17 with
a first portion 18 and a second portion 19, which underlie and are
preferably supported by a chassis 22 via downwardly depending brackets
23a, 23b and 24a, 24b. A pair of bolts, only one bolt 53 of which is
shown in FIG. 1, join upper bracket portion 23a to lower bracket portion
23b and a pair of bolts, only one bolt 54 of which is shown in FIG. 1,
join upper bracket portion 24a to lower bracket portion 24b. Chassis 22
and its brackets 23a, 23b and 24a, 24b preferably are formed of the
following commonly used metals or plastics or metal-filled plastics: (1)
an injection moldable or extrudable metal such as aluminum or zinc or (2)
a resilient, injection moldable, or extrudable plastic material such
TERLURAN-brand ABS (acrylonitrile/butadiene/styrene) resin from BASF USA
of Florham Park, N.J., USA or DELRIN-brand acetal resin from E. I. Du
Pont De Nemours and Company of Wilmington, Del., USA, or (3) Polyamide
and polystyrene, available as injection-moldable resins from Cool
Polymers, Inc., Headquarters, R&D, and Mfg., North Kingstown, R.I. USA.
Heat sinks 25 and 26, preferably located at the first and second ends of
side-light distribution arrangement 17, downwardly depend from chassis 22
and support respective LED light sources 28 and 30. In a preferred
embodiment, heat sinks 25 and 26 each contain a respective depression
(not shown) for receiving a respective LED light source 28 and 30.

[0016] LED light sources 28 and 30 preferably each comprises one or more
LEDs, all of which are provided with (i) a single pair of power leads
connected to respective pairs of electrode pins 12 and 14, (ii) a
printed-circuit board, and (iii) a single lens for conditioning light
output.

[0017] Chassis 22 provides strength for the illumination portions of the
lamp 10, while providing material suitable for gripping, in the absence
of a covering such as a transparent protective tube 21 by a user when
installing, adjusting or removing the lamp 10 from a fluorescent light
fixture (not shown). Transparent protective tube 21 may be made of, for
instance, polycarbonate. Moreover, chassis 22 can incorporate aesthetic
features, such as colors, shapes and decorative or other distinctive
features.

[0018] Chassis 22 preferably is mounted to a fluorescent lamp fixture (not
shown) by electrode pins 12 and 14. However, chassis 22 can be further
secured to a fluorescent lamp fixture (not shown) by screws, magnets, or
sturdy prongs, at each end of the chassis, in addition, or as an
alternative to, the use of electrode pins 12 and 14.

Heat Sink for LED Light Sources 28 and 30

[0019] In one embodiment, especially when composed of a metal such as
aluminum or zinc, chassis 22 can act as a heat sink for LED light sources
28 and 30, which tend to generate significant heat, which, if not quickly
removed from the LED light sources, will significantly shorten their
lifetime.

On-Board Power Regulating Circuit

[0020] Between end plate 13 and LED light source 28, a power regulating
circuit 32, shown diagrammatically, converts AC power from electrodes
(not shown) in a fluorescent lighting fixture, which engage electrode
pins 12, to DC power with a preferably constant DC current. A similar
power regulating circuit 34 may exist between LED light source 30 and end
plate 15 for converting AC power received from pins 14 to suitable DC
power for powering LED light source 30. In some embodiments, a single
power regulating circuit can provide power to both LEDs 28 and 30.
However, providing individual power regulating circuits 32 and 34 for LED
light sources 28 and 30 allows more individualized control of the LEDs,
whereby, for instance, LED light source 28 can be dimmed more than LED
light source 30.

Light-Collection Means

[0021] The first portion 18 of side-light distribution arrangement 17
receives light from LED light source 28 through light-collection means
38. Similarly, the second portion 19 of side-light distribution
arrangement 17 receives light from LED light source 30 via
light-collection means 40. The first portion 18 of side-light
distribution arrangement 17 may be physically joined to light-collection
means 38, such as with index-matching optical adhesive, or by being
integrally and gaplessly joined together with homogeneous material, such
as would result from being formed together in the same mold.

[0022] Each of light-collection means 38 and 40 has an interiorly-directed
reflective surface and is the primary device for receiving light from LED
light sources 28 or 30 and, usually through a lens, transmitting that
light toward a light-receiving portion (e.g., 18 and 19) of side-light
distribution arrangement 17. Such reflective surface is typically
specular if the light-collection means is hollow, or of the TIR-type if
the light-collection means is solid (TIR meaning Total Internal
Reflection).

[0023] Preferably, the rules of non-imaging optics govern the
configuration of the light-collection means 38 and 40, at least
approximately. As known in the art, the rules of non-imaging optics are
concerned with the optimal transfer of light radiation between a source
and a target. In contrast to traditional imaging optics, non-imaging
techniques do not attempt to form an image of the source; instead an
optimized optical system for optical radiative transfer from a source to
a target is desired.

[0024] The two design problems that non-imaging optics solves better than
imaging optics are as follows. First, (1) concentration, i.e., maximizing
the amount of energy applied to the target (as in solar power, for
instance, "collecting radiation emitted by high-energy particle
collisions using the fewest number of photomultiplier tubes"). Second,
(2) illumination, i.e., controlling the extraction of light, typically so
it is "evenly" spread over some areas and completely blocked from other
areas (as in automotive headlamps, LCD backlights, etc.).

[0025] Typical variables to be optimized at the target include the total
radiant flux, the angular distribution of optical radiation, and the
spatial extraction of optical radiation. These variables on the target
side of the optical system often must be optimized while simultaneously
considering the collection efficiency of the optical system at the
source.

[0026] Typically, a light-collection means 38 or 40 at least approximately
governed by the rules of non-imaging optics, has a profile that changes
from inlet end towards outlet end to condition the angular distribution
of light provided to a preferably rod-shaped side-light distribution
arrangement 17. That is, as light propagates through the coupler 38 or
40, its angular distribution changes following at least approximately the
rules of non-imaging optics. Three examples are as follows. First, (1)
the light may be conditioned to reduce the angular distribution of light
to be significantly below the numerical aperture or acceptance angle of
the side-light distribution arrangement 17 so that it propagates along
the entire length of arrangement 17 and is distributed out the opposite
end. In this example, not applicable here, the arrangement does not
distribute light from its side, so it is not called a side-light
distribution arrangement. In a second example (2), the angular
distribution of light leaving the coupler can be higher but closer, or
even beyond, the numerical aperture (NA) of the distribution arrangement.
In this case, the light leaving the coupler with a higher angular
distribution will see a greater number of interactions with the sides of
the side-light distribution arrangement 17, thereby increasing the
opportunity for extraction out the side of arrangement 17 over a shorter
distance. In a third example (3), the profile of the light-collection
means 38 or 40 changes so that the light leaving the collection means is
not only conditioned to cause the angular distribution to be within an
intended NA, but also is conditioned to cause the light to be uniformly
distributed among a greater number of angles. In this case, at least
approximately governed by the rules of non-imaging optics, the profile of
the collection means will typically grow in size and then decrease as it
approaches and reaches the side-light distribution arrangement 17.
Because the resulting light is conditioned so that light is present at a
multitude of angles, light with higher angles will have more interactions
with the side of the distribution arrangement and will be distributed
over shorter distances, and light with lower angles will see fewer
interactions so will be distributed over longer distances. The result can
be a more uniform extraction out of the distribution arrangement along
its entirety.

[0027] Preferably, each of light-collection means 38 and 40 have an input
that collects at least about 25 (and more preferably 75 and even more
preferably 90) percent of the light emitted by the respective LED light
sources 28 and 30, and has an output that directs over half of the light
collected at the input with an angular distribution different from that
of the light when received at the input. The angular transformation is
preferably chosen to attain a desired illumination profile along the
length of the side-light distribution arrangement 17, which may be
uniform to within about 10 percent of an average value of illumination,
for instance.

Side-Light Distribution Arrangement

[0028] As mentioned above, the side-light distribution arrangement 17
preferably has the shape of an elongated rod. By "elongated" is meant
being long in relation to width or diameter, for instance, where the
"long" dimension can be both along a straight path or a curved path. The
elongated rod has an elongated sidewall and light-extraction means 44
along at least part of the elongated sidewall for extracting light
through the sidewall and distributing said light to a target area. At
least that portion of the side-light distribution arrangement 17 having
light-extraction means is preferably solid, although there may exist in
the arrangement small voids caused by manufacturing processes, for
instance, that have insubstantial impact on the side-light extraction and
distribution properties of the arrangement. Although not shown,
light-collection means 38 and 40 may be provided with light-extraction
means (not shown).

[0029] A side-light distribution arrangement may comprise an acrylic rod,
or high-temperature glass or quartz for operation in a heated
environment, or other optically clear material such as the core of a
large core, flexible, plastic, fiberoptic light guide.

[0030] A side-light distribution arrangement typically has a cross section
along an axis of light propagation through the arrangement that is more
round than flat. For instance, the minimum cross-sectional dimension is
preferably more than 50% of the maximum cross-sectional dimension. In a
preferred embodiment, the cross-section of the side-light distribution
arrangement is substantially circular.

[0031] Preferably, a side-light distribution arrangement is rigid, by
which is meant that at 20 degrees Celsius the arrangement has a
self-supporting shape such that the arrangement returns to its original
or approximately original (e.g., linear or curved) shape after being bent
along a main path of light propagation through the arrangement.

Light-Extraction Means

[0032] Light-extraction means 44 may be of various types whose selection
will be routine to those of ordinary skill in the art. For instance,
three types of light-scattering means are disclosed in U.S. Pat. No.
7,163,326, entitled "Efficient Luminaire with Directional Side-Light
Extraction," assigned to Energy Focus, Inc. of Solon, Ohio. In brief,
these three types are (1) discontinuities on the surface of a side-light
distribution arrangement, (2) a layer of paint on the surface of a
side-light distribution arrangement, and (3) a vinyl sticker applied to
the surface of a side-light distribution arrangement.

[0033] In more detail, (1) discontinuities on the surface of a side-light
distribution arrangement may be formed, for instance, by creating a
textured pattern on the distribution arrangement surface by molding, by
roughening the distribution arrangement surface with chemical etchant, or
by making one or more notches in the side of the distribution
arrangement.

[0034] Secondly, (2) the light-extraction means could comprise a layer of
paint exhibiting Lambertian-scattering and having a binder with a
refractive index about the same as, or greater than that of, the core.
Suitable light-extraction particles are added to the paint, such as
titanium dioxide or many other materials as will be apparent to those of
ordinary skill in the art. Preferably, the paint is an organic
solvent-based paint.

[0035] Thirdly, (3) the light-extraction means could comprise vinyl
sticker material in a desired shape applied to the surface of the
distribution arrangement. Appropriate vinyl stickers have been supplied
by Avery Graphics, a division of Avery Dennison of Pasadena, Calif. The
film is an adhesive white vinyl film of 0.146 mm, typically used for
backlit signs.

[0036] Generally, the light-extraction means may be continuous or
intermittent or both along the length of a side-light distribution
arrangement, for instance. An intermittent pattern is shown in the
above-mentioned U.S. Pat. No. 7,163,326 in FIG. 15A, for instance. To
assure that the light-extraction means appears as continuous from the
point of view of the observer in a target area to be illuminated, the
target area should be spaced from the side-light distribution arrangement
in the following manner: the spacing should be at least five times the
length of the largest gaps between adjacent portions of paint or other
light-extraction means along the main path of TIR light propagation
through the side-light distribution arrangement.

[0037] Additionally, the foregoing extractor patterns can be of the
specular or scattering type, or a combination of both. Generally, a
scattering extractor pattern for light on an elongated side-light
distribution arrangement tends to provide light onto a target area, along
the length of the distribution arrangement, with a moderate degree of
directional control over the light in the length direction. In the
direction orthogonal to the length, the scattering extractor pattern
density and the cross sectional shape of the elongated distribution
arrangement provide a smooth target distribution that is free of
localized spatial structure but still provides good directional control.
Scattering extractor patterns are relatively insensitive to fabrication
errors.

[0038] In contrast, as used herein, a specular extractor pattern can
provide light along the length of a side-light distribution arrangement
with more localized control than can a scattering extractor pattern.

[0039] Light-extraction means 44 preferably extends along the length of
first portion 18 of the side-light distribution arrangement 17 for a
distance greater than 50 percent of the distance between first and second
ends of the lamp 10 as defined by end plates 13 and 15. Preferably, the
distance between the first and second ends of lamp 10 is at least about
one foot (30.5 centimeters) long. Further, the LED light sources 28 and
30 are preferably each located within about five centimeters of the most
adjacent end plates 13 or 15, with lamp 10 being free of further light
sources located between the LED light sources 28 and 30.

[0040] In regard to the relationship between the first and second portions
18 and 19 of side-light distribution arrangement 17, such portions may be
physically separate, or even optically isolated, from each other.
Alternatively, first and second portions 18 and 19 may be optically
coupled to each other, such as by being physically joined to each other,
for instance, with index-matching optical adhesive, or by being
integrally and gaplessly joined together with homogeneous material, such
as would result from being formed together in the same mold. When
portions 18 and 19 are optically coupled to each other, some light from
LED light source 28 may pass through first portion 18 and enter portion
19 and become extracted by light-extraction means 44; and, similarly,
some light from LED light source 30 may pass through second portion 19
and enter portion 18 and become extracted by light-extraction means 44.

On-Board Storage of Electrical Circuits, Etc.

[0041] FIG. 2 is similar to FIG. 1, but shows a lamp 50 whose power
regulating circuits 32 and 34 of FIG. 1 are moved to locations 33 and 35,
respectively, within chassis 51. If desired, a single power regulating
circuit 33 or 35 may power both LED light sources 28 and 30. The
preferred construction of chassis 51 is similar to that of chassis 51
shown in FIG. 3, wherein a chassis body section 51a is provided with a
chassis cover 51b for enclosing an interior volume that can hold, for
instance, power regulating circuit 33, shown as a printed-circuit board
with electrical components mounted thereon. A protective tube 56,
corresponding to protective tube 21 of FIG. 1, protects components within
the tube. FIG. 3 shows cross sections for chassis body section 51a and
chassis cover 51b representing plastic (e.g., polymer) or, alternatively,
all metal or all plastic, as described elsewhere in this specification.

[0042] Other electric circuits that may be stored in the interior volume
of chassis 51 are other printed-circuit boards ballasts, drivers,
communication devices, wireless radio devices, sensors, controllers or
any other device that can enhance the performance of LED lamp 10. For
instance, a wireless radio device (not shown) stored in chassis 51 may be
responsive to an occupancy sensor, for instance, so as to turn down or
off the LED light sources 28 and 30 when an illuminated space is not
occupied by a person. Further, for instance, a controller (not shown)
stored in chassis 51 may consist of circuitry to allow for dimming of
lights, turning off one or the other LED sources individually if there is
one or more LED source at each end of lamp 10, or dimming one or the
other LED light sources at the ends especially if the LED light sources
have different color or efficiency qualities.

[0043] Especially when composed of aluminum, zinc or another metal-filled
polymer such as polyamide and polystyrene, available as
injection-moldable resins from Cool Polymers, Inc., Headquarters, R&D,
and Mfg., North Kingstown, R.I. USA, chassis 51 can act also as a heat
sink for electronic components stored in the interior volume formed in
chassis 51.

Support of Side-Light Distribution Arrangement 17 and LED Light Sources 28
and 30

[0044] As mentioned above, chassis 22 or 51 supports side-light
distribution arrangement 17 with its downwardly depending brackets 23a,
23b and 24a, 24b, for instance, relative to electrode pins 12 and 14
shown in FIG. 2, and also supports heat sinks 25 and 26 with LED light
sources 28 and 30 preferably partially mounted into respective
depressions (not shown) in heat sinks 25 and 26. It is advantageous for
chassis 22 or 51 to support arrangement 17 and LED light sources 28 and
30 in this manner since arrangement 17 can be securely held in alignment
with respect to LED light sources 28 and 30. More particularly, the LED
light sources 28 and 30 may be held in a single position relative to
chassis 22 or 51, and side-light distribution arrangement 17 may be
similarly held in a single position relative to chassis 22 or 51. The
chassis 22 or 51 then assures proper alignment between LED light sources
28 and 30 and side-light distribution arrangement 17.

Reflector for Capturing and Redirecting Otherwise Lost Light

[0045] Preferably, chassis 51 of FIG. 2 has a downwardly facing, elongated
reflector 52, whose horizontal dimension in FIG. 3 is at least about 1.3
times the horizontal dimension of side-light distribution arrangement 17
as viewed in FIG. 3. Reflector 52 is supported by the chassis, as an
integral or attached device, and faces the side-light distribution
arrangement 17. Reflector 52 is preferably a specular, diffuse reflector.
One purpose of reflector 52 is to capture light 55 that is extracted from
side-light distribution arrangement 17 but, instead of passing downwardly
through the lower surface of side-light distribution arrangement 17 as
does downwardly directed light 58, first passes upwardly through
light-extraction means 44. The light 55 that passes upwardly through
light-extraction means 44 may typically be as much as 30 to 40 percent of
the downwardly directed light 58, and would otherwise be lost unless
efficiently captured and redirected by reflector 52, for instance. The
reflector 52 thus significantly improves efficiency of extraction of
light from side-light distribution arrangement 17. Chassis 51 also
preferably has the foregoing features of chassis 22.

[0046] FIG. 4 shows another elongated LED lamp 60, in which one or more
LED light sources 62, comparable to LED light sources 28 or 30 described
above, are used to provide light to a side-light distribution arrangement
63, via a light-collection means 64, comparable to light-collection means
38 and 40 described above. Side-light distribution arrangement 63 is
comparable to side-light distribution arrangement 17 described above,
except for its right-hand end not being provided with light from LED
light sources near the right-hand end. Rather, the right-hand end of
side-light distribution arrangement 63 may terminate with a reflector 68
for capturing light travelling from LED light source 62 to the right in
side-light distribution arrangement 63, which is not extracted from the
side of side-light distribution arrangement 63 by light-extraction means
70. Reflector 68 is preferably oriented as shown in FIG. 4 so as to
direct captured light that is re-directed to the left, as shown, upwardly
in light-distribution arrangement 63, so that the light will reach
light-extraction means 70, comparable to light-extraction means 44
described above, and be extracted from the side of arrangement 63. A
mechanical support member 69, which does not receive light from LED light
source 62, can be used to support the right-hand shown end of side-light
distribution arrangement 63. Alternatively, reflector 68 could be
omitted, and side-light distribution arrangement 63 could extend all the
way to end plate 15, for instance. A protective tube 71, corresponding to
protective tube 21 of FIG. 1, protects components within the tube.

[0047] In FIG. 4, chassis 72, comparable to chassis 22 described above,
has downwardly depending brackets 73a, 73b and 74a, 74b, comparable to
brackets 23a, 23b and 24a, 24b described above, for supporting side-light
distribution arrangement 63. A pair of bolts, only one bolt 80 of which
is shown in FIG. 4, join upper bracket portion 73a to lower bracket
portion 73b and a pair of bolts, only one bolt 81 of which is shown in
FIG. 4, join upper bracket portion 74a to lower bracket portion 74b. A
heat sink 75, comparable to heat sink 25 described above, preferably
located at the first end of side-light distribution arrangement 63,
downwardly depends from chassis 72 and supports respective LED light
source 62. In a preferred embodiment, heat sink 75 contains a respective
depression (not shown) for receiving a respective LED light source 62.

[0048] In LED lamp 60 of FIG. 4, only electrode pins 12 receive electrical
power for LED light source 62, via a power regulating circuit 78
contained in an'interior volume of chassis 72, in the same manner as
shown in FIG. 3 for power regulating circuit 33 contained in an interior
volume of chassis 22. Alternatively, power regulating circuit 78 could be
positioned between LED light source 62 and electrode pins 12, in the same
manner as, in FIG. 1, power regulating circuit 32 is positioned between
LED light source 28 and electrode pins 12.

[0049] The following is a list of reference numerals and associated parts
as used in this specification and drawings:

[0102] The foregoing describes an elongated LED lamp that is suitable for
replacing a fluorescent lamp in a fluorescent lamp fixture. The lamp
includes a chassis having benefits ranging from allowing an installer, in
the absence of an outer protective tube, to grip the lamp while
protecting illumination portions of the lamp, serving as a heat sink for
one or more LED light sources in one embodiment, and providing an
enclosed compartment for inclusion of various electrical circuits such as
a power regulating circuit for an LED light source and a wireless circuit
dimming the lamp when no person occupies an illuminated space.

[0103] While the invention has been described with respect to specific
embodiments by way of illustration, many modifications and changes will
occur to those skilled in the art. For instance, such directionally
dependent terms as "downwardly," "top," etc., are used herein merely for
ease of explanation and not in a limiting sense. It is, therefore, to be
understood that the appended claims are intended to cover all such
modifications and changes as fall within the true scope and spirit of the
invention.